Safety appliance for electrically heated apparatus



Nov. 8, 1932. w. H. BULPITT SAFETY APPLIANCE FOR ELECTRICALLY HEATED APPARATUS Filed Dec. 23, 1951 FIG,

Wnifer Ham's Eu! 93+ M I AWJ Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE WALTER HENRY BULPITT, OF BIRMINGHAM, ENGLAND Application filed December 23,

This invention relates to safety appliances for electrically heated apparatus and refers more particularly to that kind of apparatus wherein automatic means are provided for switching off the current when the apparatus has been heated to a certain predetermined temperature.

For instance, the invention is particularly applicable to electrically heated cookin and 19 heating appliances, the arrangement being such that the current is cut off if the water or liquid in the utensil is all evaporated so that the utensil itself will not be damaged by over-heating.

Further, the invention relates particularly to that kind of apparatus wherein an electric connector is automatically disconnected from the heater by means of a spring pin or member normally retained in an inoperative position by a soldered joint or a joint made by other fusible metal, the arrangement being such that the connector is disconnected when the solder or fusible metal melts.

One of the objects of the present invention 2 is to provide an improved construction of safety appliance wherein the action of resetting the soldered joint will be more certain than hitherto.

Referring to the drawing Figure 1 is a plan view partly in section showing one form of the apparatus constructed in accordance with the present invention.

Figure 2 is a side view in section showing the apparatus upon an enlarged scale.

Figure 3 is a perspective view showing the parts separated.

In the construction illustrated, the heater is shown at 1 and is provided with an in- I sulating block 2 having contact pins 3 adapted to be engaged by the socket member 4 of a connector.

The block 2 is provided with a hole 5 which receives the safety member 6 constructed in accordance with the present invention, this member being in two main parts (see Figure 2), one of which consists of an inner pin 7, and the other of which consists of an outer socket 8.

The inner pin 7 is made to screw int... a

1931, Serial No. 582,749, and in Great Britain June 5, 1931.

block 9 forming part of the heater, and this pm 7 carries a catch member 10 which is fixed in position by solder or fusible metal.

The pin 7 is provided with a cup-like recess 11 which contains the solder or fusible metal, and the catch 10 is provided with a lateral trunnion 12 which is placed in the recess 11.

The free end 13 of the catch member 10 is formed as a nose having an inclined outer surface 11 and a right angled shoulder 15.

The pin 7 is further recessed at its end as shown at 16, and in the recess 16 is placed the spring 17.

The side of the pin 7 is provided with a longitudinal slot 18 which can be seen clearly in Figure 3, and the main part of the catch 10 lies in this slot. The slot 18, however, is considerably wider than the arm of the catch 10 so that the catch 10 can make a pivotal I movement from side to side about its end 12 when the solder or fusible metal is melted. l

The second main member 8 is shown clear- 'ly in Figure 3 and is formed as a thin metal socket, opposite sides of which are split as shown at 19 so that the socket as a Whole is 7 resilient in one direction.

At its open end the socket is provided with lips or flanges 20 and 21, and the side at which the lip 21 is provided, is provided with a slot 22 in which engages the nose 13 of the catch 10.

The slot 22 is provided with a projection 23 at one side having a face 24 which is at right angles to the direction of movement of the two main parts, and having a face 25 which is inclined thereto.

Further, the opposite side of the slot has an incline 26 which is opposite to the incline 25 and a further incline 27, the arrangement being such that normally the nose 13 of the catch 10 is pushed under the projection 23 which can move to allow the nose to pass by virtue of the elasticity resulting from the slots 19. The catch 10 is now fixed by the solder or fusible metal and cannot move sideways so that it retains the parts 7 and 8 in the position shown in Figure 2, the face 15 of the nose 13 engaging the incline 25.

"When the solder or fusible metal melts, however, the catch 10 is able to make a pivotal movement about the part 12, the nose 13 being now free to move sideways which it does, sliding down the incline 13 and allowing the spring 17 to push the socket 8 endwise so that the connector 4 is pushed off the contact pins 3.

Before the movement is completed, however, the nose 13 engages the second incline 27 on the member 8 so that the catch 10 is moved thereby back to its original position in relation to the member 7.

As soon as the solder or fusible metal cools, the catch becomes fixed in this position so that if the member 8 is now again pushed on to the member 7 with the spring 17 in between them, the catch 10 will again function to retain the parts together enabling the connector to be rc-engaged on the pins 3.

\Vhat I claim then is 1. Safety appliance for electrically heated apparatus comprising in combination two main members slidably associated together,

, one ofsaid main members having a cup-like recess, a catch having a portion located and normally soldered in said recess, a spring tending to slide said main members apart, and means on the catch operating to prevent relative endwise movement of the two main members under pressure of said spring, said catch being movable, when the solder melts, into a position permitting of relative endwise movement of said main members under pressure of the spring.

2. Safety appliance for electrically heated apparatus comprising in combinationtwo main members slidably associated together, one of said main members having a cup-like recess, the other of said main members having a projection with one side inclined to the direction of the sliding motion of the main members, a catch having a portion located and normally soldered in said recess, a spring tending to slide said main members apart, and a nose on the catch normally engaging the inclined side of the projection and preventing relative endwise movement of the two main members, said catch being movable, when the solder melts, into a position permitting of relative endwise movement of said main members under pressure of the spring.

3. Safety appliance for electricallyheated apparatus comprising in combination two main members slidably associated together, one of said main members having a cup-like recess, a catch having a portion located and normally soldered in said recess, a spring tending to slide said main members apart, means on one of said main members for engaging with said catch normally to prevent endwise movement of the main members but, when the solder melts, to move the catch first into a released position permitting of endwise movement of the main members, and

5 then to return it to its original position.

4. Safety appliance for electrically heated apparatus comprising in combination a pin having a cup-like recess in one side, a socket mounted for sliding movement on said pin, a spring operating between the pin and the socket and tending to slide them apart, a catch having a trunnion located in said recess and normally fixed therein by solder, said socket having a. longitudinal slot, a projection on said socket extending into said slot and having one side inclined to the axis of the socket, and a nose on the catch normally engaging the inclined side of the projection and preventing relative endwisemovement of tlie two main members, said catch being moved aside by said projection, when the solder melts, to permit the pin and socket to make relative endwise movement under pressure of the spring.

5. Safety appliance for electrically heated apparatus comprising in combination a pin having a cup-like recess in one side, a socket mounted for sliding movement on said pin, a spring operating between the pin and the socket and tending to slide them apart, a catch having a trunnion located in said recess and normally fixed therein by solder, said socket having a longitudinal slot, inclined sided projections on opposite sides of said slot, and a nose on said catch normally engaging in said slot, said nose being engaged successively bysaid projections when the solder melts, whereby said catch is rocked to one side and back again.

6. Safety appliance for electrically heated apparatus comprising in combination a pin having a cup-like recess in one side, a socket mounted for sliding movement on said pin, a spring operating between the pin and the socket and tending to slide them apart, a catch having a trunnion located in said-recess and normally fixed therein by solder, said socket having a longitudinal slot, a project'ion on said socket extending into said slot and having one side inclined to the axis of the socket, and a nose on the catch normally engaging the inclined side of the projection and preventing relative endwise movement of the two main members, said catch being moved aside by said projection, when the solder melts, to permit the pin and socket to make relative endwise movement under pressure of the spring, said socket being slit longitudinally at each side of said slot, whereby the slotted portion is resilient and capable of being sprung over said nose when resetting.

7. Safety appliance for electrically heated apparatus comprising in combination a n havmg a cup-like recess in one side, a socket' mounted for sliding movement on said pin, a spring operating between the pin and the socket and tending to slide them apart, a

catch lever having a trunnion at one end normally soldered in said recess but acting as a pivot when the solder melts, said socket having a longitudinal slot, inclined sided projections on opposite sides of said slot, a nose on said catch normally engaging in said slot, said nose being engaged successively by said projections when the solder melts, whereby said catch is rocked to one side and back again, and said socket being slit lon itudinally at each side of said slot, where y the slotted portion is resilient and capable of being sprung over said nose when resetting.

8. Safety appliance for electrically heated apparatus comprising in combination two main members slidably associated together, one of said main members having a cup-like recess, a catch lever having a trunnion at one end normally soldered in said recess but acting as a pivot when the solder melts, a spring tending to slide said main members apart, and means on the catch operating to prevent relative endwise movement of the two main members under pressure of said spring, said catch being movable, when the solder melts, into a position permitting of relative endwise movement of said main members under pressure of the spring.

In witness whereof I afiix my signature.

WALTER HENRY BULPITT. 

